Thirty-eight. The number seems innocent enough, until you think about the scope of what it represents. The Dallas Cowboys had 38 individual games missed by defensive starters while they were on Injured Reserve.

13 from safety Barry Church.

15 combined from linebackers Sean Lee and Bruce Carter.

Three from cornerback Orlando Scandrick.

Thirty-eight. And that number doesn’t include the games missed by players like safety Matt Johnson, defensive end Ben Bass, and linebacker Orie Lemon—all of whom weren’t starters but were still placed on IR—or the games missed by key players who didn’t make it to IR, such as nose tackle Jay Ratliff, outside linebacker Anthony Spencer, inside linebacker Dan Connor, and defensive end Sean Lissemore.

All told, the Cowboys lost an average of 11.2 individual games per week to injury—the majority by the defense. An incredible 91 total games were lost by players on IR. Since 2009, the ‘Boys never had more than 47 games missed by players on IR. Their poor 2012 luck is really historic.

When we assess Rob Ryan’s 2012 defense, there simply needs to be an asterisk next to the numbers. The “no excuses” excuse is certainly valid in many cases, but only up to a point. No defensive coordinator can be expected to lead a defense to even league-average numbers when he’s working with four of his original starters.

Looking ahead to 2013, there’s a lot of talk about what the Cowboys can do to prevent more injuries in the future. The truth is that, although high injury rates are fairly strongly correlated with losing, there’s not much to do to stop them. The team can certainly take some preventative measures to ensure that needless injuries don’t occur, but the majority of what we view as “injury-proneness” is simply poor luck. In any sample of players (or teams), some will get injured a whole lot and others close to never, but if past injuries aren’t predictive of future ones (which they aren’t, at this point), there’s not much a team can do.

The good news is that the Cowboys’ injury rates are extremely likely to regress in 2013. That doesn’t mean they’ll incur fewer than normal simply because they were unlucky in 2012, but rather that, as is the case every year, Dallas is most likely to have an average number of injuries. If the team sees closer to their mean of 7.5 individual games missed per week, Ryan’s defense will be ranked in the top 10 in the NFL in 2013.